image map: background-color?

I’m using a gif with transparent areas; these function as the clickable areas in an image map. They work fine.

I’d like them to turn a color when hovered over. I’ve tried

.crack{
background-color:transparent}
.crack:hover{
background-color:red}

and also
area.crack {…

but neither plays when called with <area class=”crack”…>

Using html strict dtd, testing in Firefox. Any suggestions?

Also in #CSS _↴